SAN DIEGO — Authorities found no gunman or signs of a shooting on Tuesday after receiving a report from a Department of Defense employee that shots had been heard at one of the nation's largest Naval medical facilities.
The report grabbed attention across the nation and led to the shutdown of Naval Medical Center San Diego in Balboa Park, near the San Diego Zoo, and three nearby schools.
Fears were heightened when the medical center posted on its Facebook page that, "An active shooter has just been reported in building #26 at Naval Medical Center San Diego. All occupants are advised to run, hide or fight."
The unidentified Department of Defense employee who made the report said the gunshots were heard just before 8 a.m. on the sprawling 78-acre campus, where Building 26 houses administrative offices, a gymnasium and dormitories for combat-wounded veterans in long-term care. As many as 800 people work in the building.
All non-emergency personnel were asked to stay away from the area and traffic backed up around the facility during the morning rush hour.
Military personnel searched the structure for about two hours before saying there were no initial signs of a shooting.
The base remained on lockdown hours later as military police went room to room and led personnel out of the building.
"As of right now we have found absolutely nothing that indicates there were any shots fired," said Capt. Curt Jones, commanding officer of Naval Base San Diego.
Jones said the employee reported in person what they had heard. There was construction going on nearby, but Jones said he did not know if that noise was mistaken for the sound of gunshots.
The Navy took appropriate steps in response to the report by locking down the facility and warning people of a possible shooter, he said. Numerous agencies — including the FBI, Homeland Security and police departments — offered assistance, he added.
"Obviously there's been numerous events throughout the country and truly around the world, so we take this all very, very seriously," he said.
After the initial search, TV images showed uniformed Navy personnel walking outside the medical facility. Their hands were in the air and they were being patted down by base police as a precaution.
More than 6,500 military, civilian, contractor and volunteer personnel work at the 272-bed, multispecialty hospital and ambulatory complex.
Sharie Jarsulic, a teacher at the base child care center, waited in her car outside the main gate after being denied entry. Her work day begins after employees drop off about 200 children.
The response was justified, she said, pointing out that the hospital treats mentally ill people and military members traumatized by war.
"They acted the right way," she said while waiting for the gate to reopen. "It could be someone inside or in the barrack and they could have just went off."
The facility is affiliated with 19 civilian nursing schools, training more than 400 students per year in clinical rotations. It is a leading center for medical research and has treated numerous combat veterans and Afghan and Iraqi civilians from the recent conflicts.
AP writers Christopher Weber and John Antczak in Los Angeles contributed to this report.